fifth Definition

one that is number five in a series

the musical interval embracing five diatonic degrees

a tone at this interval; specifically : dominant

a group of secret sympathizers or supporters of an enemy that engage in espionage or sabotage within defense lines or national borders

an acute virus disease especially of children caused by a parvovirus (species Human parvovirus B19 of the genus Erythrovirus) and manifested by a blotchy red rash on the cheeks which spreads to the extremities and is usually accompanied by fever and malaise

a horizontal wheel or segment of a wheel that consists of two parts rotating on each other above the fore axle of a carriage and that forms support to prevent tipping

a similar coupling between tractor and trailer of a semitrailer

one that is superfluous, unnecessary, or burdensome

to refuse to answer questions in a court of law because the answers might be harmful to one or might show that one has committed a crime —often used figuratively